81481340 has 48 divisors (see below), whose sum is σ = 181948032. Its totient is φ = 30544896.

The previous prime is 81481339. The next prime is 81481373. The reversal of 81481340 is 4318418.

It is a plaindrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124454 + ... + 125106.

It is an arithmetic number, because the mean of its divisors is an integer number (3790584).

Almost surely, 2^81481340 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81481340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90974016).

81481340 is an abundant number, since it is smaller than the sum of its proper divisors (100466692).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81481340 is a wasteful number, since it uses less digits than its factorization.

81481340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1046 (or 1044 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 81481340 is about 9026.7015016561. The cubic root of 81481340 is about 433.5302313615.

Adding to 81481340 its reverse (4318418), we get a palindrome (85799758).

The spelling of 81481340 in words is "eighty-one million, four hundred eighty-one thousand, three hundred forty".